It is an unfortunate but inevitable fact that from time to time, for a range of reasons, vehicles crash. In such circumstances, the design of the vehicle is a significant factor in whether the occupants survive and, if so, whether and to what degree they are injured.
Care is therefore required in the design of vehicles, to ensure that adequate protection is offered to the driver and passengers under a severe impact. Crumple zones are common, being an energy-absorbing structure within the vehicle chassis that is designed to deform under impact and (in doing so) absorb the energy of the impact.
Particular difficulty is encountered in relation to small city cars, since their small dimensions mean both that there is little space for energy-absorbing structures and that the vehicle occupants are physically closer to the point of impact. The “Smart Car” (as sold in various markets by MCC Smart GmbH from 1998 onwards) employed a rigid safety cell around the occupants in combination with a small crumple zone, the intention being to deflect the impact energy around the occupants whilst it is being absorbed by the (assumed) larger crumple zone of an impacting vehicle.
WO2009/077079 addresses the specific problem of the wheels intruding into the passenger cell, by locating a crumple zone behind the front wheels, defining the rear portion of the wheel arch. A wheel that is forced rearwards in a frontal collision is caught by the crumple zone and made less likely to enter the passenger cell where it might injure an occupant.